Passengers told CNN that Tuesday night's ordeal began when they were diverted to Bradley because of bad weather during a flight from London to Newark, N.J. They said they landed at about 8:20 p.m. and were kept on the plane until about 1 a.m. Wednesday.

Passengers told the news network that people were yelling and screaming. At least three people fainted and were taken away in ambulances, passengers said. The aircraft was carrying 300 passengers and 14 crew.

"It was like four hours on the ground without any air conditioning. It was crazy. Just crazy," passenger Beth Willan told CNN. "There were babies on the plane. And we are in dark and hot. You try to be patient but people were yelling and screaming."

Virgin Atlantic's London office confirmed to The Associated Press that Flight VS001 on the A340-600 jet was diverted because of bad weather in the Newark area. Airline officials said the passengers were being bused to Newark on Wednesday morning.

"Virgin Atlantic would like to thank passengers for their patience and apologise for any inconvenience cause," the statement said.

A Virgin spokeswoman in London told the AP on Wednesday that Bradley Airport "isn't used to dealing with international flights" and had to call customs and immigration officials back to the airport Tuesday night to process the passengers. She said the airline was forced to keep people on the plane.

"It was a situation that was beyond our control," said the spokeswoman, who refused to give her name. "There were weather conditions. ... Bradley had to get customs and immigration to the airport."

The spokeswoman said she believed passengers were kept on the flight for about three hours. She said the planes have water fountains aboard, but she wasn't sure if any food was left over after the in-flight meals had been served.

Ken Cast, an airport operations specialist, said Virgin is not one of the airport's carriers and the airline had to call in personnel to handle the passengers.

"Being an international flight, it's not like you can let people wander aimlessly," Cast told the AP. "They need to be processed, and they need to be kept safe. Everyone has to clear customs.

"The rules still need to be followed," Cast said. "Everyone was safe. They may have been uncomfortable, but they were safe. It's better to be on the ground wishing you were somewhere else than to be in the air wishing you were on the ground."

Cast confirmed that a few passengers who weren't feeling well were treated by paramedics. Details on the sick passengers weren't immediately available.

A new federal rule on flights stuck on runways that went into effect in April bans U.S. carriers from making passengers wait on planes for longer than three hours. International airlines are not subject to the 3-hour delay rule, even if they land or takeoff from U.S. airports.

The Obama administration has proposed extending the requirement to international flights and making sure international carriers have contingency plans to handle passengers who've been kept waiting for long periods.